Slug detector



Jam. 16, 1940.

w. c. MITCHELL SLUG DETEC'IGR Filed March 9, 1936 2 Sheets-Sheet 2 ATTORNEYS' Patented Jan. 16,1940

' L :i ii

PATENT, OFFICE SLUG DETECTOR William C. Mitchell, Strati'crd, Conn.

Application March 9, 1936, Serial No. 67,826

5 Claims.

This invention relates to new and useful improvements in coin controlled apparatus and has particular relation to a means for detecting n g n An object of the invention is to provide a. means I for preventing operation of nickel (five cent coin) controlled devices unless a nickel is inserted into such devices, or to separate slugs from nickel coins.

Other objects and advantages will become apparent from a consideration of the following detailed description taken in connection with the accompanying drawings wherein satisfactory embodiments of the invention are shown. However, it will be understood that the invention is not limited to the details disclosed but includes all such variations and modifications as fall within the spirit of the invention and the scope of the appended claims. I

In the drawings: I

Fig. 1 is a view partly in elevation and partly in section and showing one form of the invention;

Fig. 2 is a sectional view taken substantially along the line 2-2 of Fig. 1:

Fig. 3 is a sectional view taken along the line 3-3 of- Fig. 1;

Fig. 4 is a view partly in section and showin a modified construction;

Fig. 5 is a. view at right angles to Fig. 4;

Fig. 6 is a sectional view taken substantially along the line 66 of Fig. 4;

Fig. 7 is a view partly in section and partly in elevation, and showing another modification; and

Fig. 8 is a sectional view taken substantially along the line 8-8 of Fig. 7. v

The present invention is based on the discovery that if certain metals, preferably high carbon steels, are rubbed across a nickel (a United States five cent coin) or if the nickel is rubbed across such metals an electric current, sufflcient to operate a sensitive high speed meter, as a galvanometer or milliammeter, is generated. My tests indicate all kinds of iron and steels in particular have this effect, and it seems the harder the steel or closer the grain the better is the effect. The high carbon steels are particularly good, such as that used for phonograph needles. Steel like drill rod, high speed, tool and machine steels worked well. I have also found the coppernickel-zinc alloy known as 22% nickel silver" worked fairly well and thus indicates there are probably other specific alloys which could be used. The movement of the arm or pointer of the meter substantially (Cl. l94100) due to the energizing of the meter by the generated current can be used to release the mechanism being guarded and which mechanism may be a telephone, dispenser, etc.,

I have found that the wiping of the high carbon steel or similar material across any of the ordinarily easily available metals or alloys other than that of alloys composed principally of large proportions of both copper and nickel and especially the alloy containing a large amount of copper and nickel of -which five cent coins are made will not generate sufficient current tooperate the meter. The various common metals available and from which slugs are usually made cannot be used to generatethe necessary current. This is true of pure nickel, cobalt, and of various brasses from low to high brass, bronzes and coppers. White gold will give about one-fifth of the effect of the nickel coin.

.Various arrangements of trip mechanisms may be employed or associated with the pointer or arm of the meter employed so. as to be controlled thereby. Three arrangements are shown in the accompanying drawings although it is to be understood that the invention is not limited to the particular arrangements disclosed.

Referring now particularly to Figs. 1. 2 and 3, at Ill is shown a casing or housing having therein a substantially Y-shaped chute including a vertically disposed main arm or passage ii and mm wardly inclined passages or arms l2 and I3 at the lower end of the passage ll. At the upper end of the passage H is a housing l4 forming a cross passage IS in communication with passage H, and operable in the passage i5 is a slidable-device or carrier l6 including a metal block or plate I! having a slot or opening 18 extending vertically through it and of a size to receive a nickel coin IS.

The plate ll is shiftable from the full line position of Fig. 1 to the dotted line position thereof, and when the plate is in the full line position its slot 18 is registering with a slot 20 in the upper wall of the housing l4 so that the coin l9'may be inserted in the slot 18 through the upper end thereof. On the plate being shifted to the dotted line position the lower end of its slot I8 registers with the upper end of the chute laterally providing a housing portion 23 at the slotted side of the plate II. Within such housing portion a spring arm 24 is mounted as on a support 25 and the outer or free end of such arm carries a pin 26 of high carbon steel or other suitable metal. This pin 26 has its inner end portion bevelled as at 29, and the pin extends through the slot 2| and under the urging of the spring 24 is normally maintained with its inner end in engagement with the wall of the plate opposite that having the slot 2|. It is noted that except for this engagement of the inner end of the pin with the plate I! the pin is insulated from the plate by the insulating strip 22 and by insulating the mounting 25 of the spring arm 24.

The housing mounting plate I! has a. tubular extension 30 through which a tube 3I enters the housing and the inner end of such tube 3I is threaded or otherwise secured to the plate II. About tube 3I a coil spring 32 is arranged, and such tube at diametrically opposite points is slotted at 33 to accommodate a pin 34 carried by the inner end of a rod 35. Pin 34 extends at opposite sides of the tube 3| so that on the rod 35 being forced forwardly in the tube the spring 32 will be compressed if slide I! does not move. The outer end of rod 35 is secured to a head 36 and the latter is in turn secured to a sleeve 31 adapted to be telescoped over the housing extension 30 as will later appear. Within such sleeve and about the rod 35 is a spring 38 bearing at one end against the outer end of the tubular housing extension 30 and at its other end against the head 36.

It is noted that while the pin 26 is in normal position it extends across one edge of a coin I9 inserted in the slot I8 and being in the path of movement of the coin tends to prevent movement of the plate I I in a direction to carry the coin over the chute I I. The spring 38 normally keeps the head 36, sleeve 31 and rod 35 in the outer position shown in Fig. 1, and the pin 34 at the inner end of the rod engaging the outer ends of the slots 33, the sleeve 3| and plate I1 are kept in normal position.

When acoin has been placed in the slot I8 the head 36 is pressed inwardly telescoping the sleeve 33 over the housing extension 30 and moving the rod 35 inwardly. As the rod moves inwardly it acts through the pin 34 to cause compression of the spring 32. Up to a certain point, the pin 26 being across the forward edge of the coin I9, inward movement of the coin and of the plate I1 is prevented. However, the edge of the pin toward the coin is bevelled and when the spring 32 has been sufficiently compressed so as to overcome the holding action of the pin 26 the latter is cammed outward as to the dotted line position of Fig. 3 and the spring 32 expanding snaps the plate I I and the coin I3 to an inner position disposing the coin over the upper end of the chute II.

As the coin is thus shifted inwardly it is rubbed across the inner end of the pin 36 and an electric current is generated if the coin and pin are in a closed circuit. On release of the hand piece 36 the plate or slide I1 and its associated parts are returned to normal position by the spring 38 although it will be understood that before this occurs the coin drops out of the slot I8 into the chute I I.

A wire 39 connects the spring 24 and thereby the pin 26 with the coil 40 of a suitable galvanometer or meter 4| while a wire 42 connected with the plate I! also connects with such coil 40.

From this it will be clear that when the pin 26 is in engagement with such plate the coil 40 is short circuited preventing the coil and needle from swinging from a jar or the like. The meter 4I also includes the usual permanent magnet shown as a horse shoe magnet 43 and further includes a needle or arm 44 adapted to be shifted on energizing of the coil 40. In this connection it will be appreciated that with the arrangement shown any current generated by the wiping of the coin I9 across the pin 26 will be impressed on the coil of the meter 4| so as to cause shifting of the arm 44.

A bar or lever 45 is provided with a pivot 46 mounted in the bearings 41 and it is noted that such pivot 46 is arranged at right angles to the pivot 48 carrying the meter pointer or arm 44 and in turn mounted in bearings 49. The bar 45 extends along one side of the coin chute and toward one end carries a pin 50 projecting into the coin chute through an arcuate slot SI and normally occupying a position extending across the branch I2 at the upper end thereof as shown by the full lines in Fig. 1. The end of the bar opposite that carrying pin 50 is counterweighted as at 52 and extends under the meter arm 44 when the latter isin its normal full line position. When bar 45 is in its normal horizontal position its counterweighted end is resting on a stop pin 53 and is at the underside of the arm 44 so that the bar is held against movement about its mounting pivot.

Extending across the upper side of the meter arm 44 is a bar 54 mounted as on supports 55 and such bar backs up and prevents vertical movement of the arm 44 under action of bar 45, although it is to be understood that there is no engagement between these parts unless the arm is forced upwardly against the bar. Securrc to and extending downwardly from the weighted end of the bar 45 is a curved wire or tail 56 the purpose of which will later more fully appear.

When using the apparatus a coin, as the coin I9, is placed in the slot I8 and thereafter the head 36 is pressed inwardly. This results in spring 38 being compressed, and as the rod 35 and its pin 34 are moved inwardly spring 32 is compressed and is pressing inwardly on the plate I! so that the coin I9 is being forced against the pin 26. When the spring 32 has been compressed to such an extent that the pressure exerted by it is sufficient the engagement of the coin with the inclined or cammed end 39 of the pin 26 results in the latter being forced into the dotted line position of Fig. 3 then free to expand snaps the plate H from the full to the dotted line position of Fig. 1. The coin I9 is carried with the plate into a position over the upper end of the chute II and as the coin is thus shifted it is wiped across the inner end of the pin 26. slots 33 may be positioned so as to be engaged by pin 34 just before the limit of its inward movement so as to give a positive push or start to slide I1 and then its inward movement will be completed under action of spring 32.

If the coin is a nickel (a United States five cent piece) an electrical current is generated and is impressed on the coil of the galvanometer or meter H with the result that the meter arm 44 is shifted from the full line position extending over the counter-weighted end of bar 45 to the dotted line position beyond the end of said bar. Therefore on the meter being energized its arm 44 is carried out of a position locking the bar 65 and the spring 32 being If desired the inner ends of.

will not be energized and and such bar may be tilted into the position suggested by the dotted lines in Fig. 1. The bar 45 does not move of its own accord on shifting of the needle arm 44 but the bar is released and the coin dropping through the chute part II strikes the pin 50 and causes the bar, 45 to rock shiftingthe pin downwardly in the slot so as to carry it out of the chute'portion l2 and permit the coin to pass downwardly through such chute portion. The coin as it passes down chute l2 may be used to release or trip any desired mechanism such for example as a dispensing mechanism, close a telephone circuit connection. etc., as desired.

As the coin rocks the bar the tail 56 is carried with the bar into a position in the path of the return movement of needle arm 44 thus pre venting the arm 44 from making its return movement until the bar drops, since such arm as it tends to return to normal position engages the tail 56 and is prevented from moving under the counter-weighted end of the bar. When the coin moves beyond the pin the bar rocks back to normal horizontal position and as it reaches such position the meter arm 44 is free to return to normal position extending across the upper side of the counter-weighted end of the bar.

When the coin fed to the machine is other than the United States nickel or five cent piece an electrical currentsufilcient to operate the meter is not generated by the wiping action between such coin and the pin 26 and therefore the meter 4| its arm 44 will remain in position extending across 64 against upward pressure of lever or bar 45.

Thus when the coin offered drops on to the pin 50 the latter will be held against movement and the coin will be prevented from moving down the chute arm or portion I2 but will be caused to move down the arm or portion l3 which may conduct it to a suitable receptacle or return it to the outside of the machine as desired. From this it will be understood that after a coin is presented to the machine the meter 4| determines the fur'- ther disposition of the coin, and if the coin is a nickel it moves along one path and if it is not a nickel it is caused to move along some other path. My experiments with the present invention have led to the conclusion that it is only by the wiping action between a nickel coin and the pin 26 or its equivalent that an electrical current sufficient for the present purpose will be generated. If a slug of any other 'ordinary metal or alloy, at" least of the kinds of which slugs are usually made, is inserted into the machine the necessary electrical current will not be generated. Pure nickel, cobalt, and all kinds of bras'ses from the low to high brass bronzes and coppers have been tried without success The'only coin or the onlymetal I have found from testing a large number of metals and alloys available which gives the desired proportions far the best results and of both copper and nickel, and by greatest meter arm movement were secured with the special alloy, or

one similar to it. used in making the United States nickel or five cent coin, and it is to be understood that in this application the word nickel refers to the coin of the United States known by that name or to a slug made from the alloy of that coin. equivalent part which is to have a wiping action with the coin so as to generated the necessary electrical .current is preferably of high carbon steel something like that of a phonograph neethe upper side of the bar 45, the needle arm 44 being backed up by bar results are alloys composed of large While the pin 26 or the dle), the invention is not limited to this particular metal since other irons and steels as men tioned above and possibly other metals may be used with reasonably satisfactory results.

Referring now to Figs. 4, 5 and 6 a portion of a housing or casing is shown at 60 and the same is provided inits upper end with a slot 6| leading into a vertically'disposed chute portion 62 having diverging branches 63 and 64 at its lower end corresponding with the chute portions l2'and I3 of Fig. 1. first described. Within the housing 60 and arranged at right angles to and entering and extending at each side of the chute portion 62 is a slot 65.

Accommodated by the part way in to the chute 62 from opposite sides thereof are a pair of metal shoes 66 and '61 mounted as by pins 68 located in slots 69. Light leaf springs 10 carried by the shoes 66 and 61 bear against blocks of insulation 1| and normally act to urge the shoes toward one another and this tendency of the springs is checked or limited when the p 58 ain the inner ends of the slots 10 as shown in Fig. 4. Insulating pieces '12 located in the slot at opposite sides of the chute 62 are pivotally mounted at 13 and secured to the respective pieces and extending upwardly from them are conducting bars or wires 14 and 15 at their upper ends carrying curved inwardly directed contact pieces 16 and I1 normally in engagement. Straps I8 and T9 electrically connect thesh'oe 66 with the conductor 14 and the shoe 61'with the conductor 15, respectively.

Wires and 8| corresponding respectively with the wires 39 and 42 of Figs. 1 through 3 serve to connect the shoes 66 and 61 with the meter 4|. Secured to the insulating pieces 12 and extending slot 65 and extending downwardly from them are bars or wires 82 and 83 at their lower ends carrying curved inwardly directed. cam pieces 84 and 85' adapted to be brought into engagement or sufficiently close to be shifted by the coin as will later appear. Since the contact pieces 16 and 11 are normally in engagement and the bars or wires 74 and l5are connected with the respective shoes by the straps I8 and 19 and such shoes are connected with the coil in the meter by the wires 8|) and 8| it will be apparent .that such meter coil is normally in a closed circuit and therefore shorted so it will not swing under a jar or movement of the box or case carrying the device.

On insertion of the coin (nickel or slug) 86 through the slot 6| it engages the contacts 16 and 1,1 and forces them apart or outwardly causing rocking of the insulating pieces 12 about their .pivots l3 and this movement of the insulating pieces causes the bars or wires 82 and 83 tobe swung toward one another whereby thegcams 86 and 85 carried by such bars or wires are moved inwardly toward each other. The'shoes 66 and 6? are spaced apart a distance slightly lessthan the while the other is of some other metal such as for example copper, it being understood that one shoe is of the material of pin ZS-and has the same effect. As the nickel moves downwardly between the shoes it wipes against them and a current is generated and impressed on the coil of the meter so as to have the meter act in the manner previously described. If the coin is a slug or of other metal than the alloy of the United States five cent piece no current will be generated and the galvanometer or meter needle will not be shifted. It will be apparent that the meter may control any desired tripping mechanism but as suggested here the bar 45 and pin 50 and the associated mechanism of Figs. 1 through 3 may be employed in connection with the generating means of Figs. 4, 5 and 6. As the nickel passes from between the lower ends of the shoes it engages the cams 04 and 05 forcing them apart in a manner to rock the insulating pieces 12 about the pivots 13 so as to carry the contacts I6 and I1 back into engagement to again short circuit the meter coil.

Figs. 7 and 8 show yet another modification wherein an apparatus embodying the principles of the invention is shown in which the steel contact is wiped across the coin instead of the coin moving over the contact. It is shown as arranged in association with a pay station telephone but this is merely illustrative as it may be used to control any other type of coin controlled device. In these figures a housing or casing 90 is provided with a coin entrance slot 9| leading to a vertical chute portion 02 from the lower end of which extend diverging chute portions 93 and 94 corresponding with the chute portions II, I2 and I3 of Fig. 1. A pair of dogs 95 each pivoted as at 96 are normally held in positions extending into the chute 92, by means of coil springs 91, and each such dog includes an extension 98 maintained against a stop pin 09 whereby movement of the dogs under the influence of the springs is limited.

An arm I00 extends at one side of the chute 92 and such arm is carried by pivot IOI about which is arranged a spring I02 having an end portion I03 extending beneath the arm I00 and normally tending to shift the arm to the dotted line position of Fig. '7 and to maintain it in such position. This arm I00 includes a section I04 which may be described as the pivoted section and further includes an outer section I05 hinged to the section I04 at I06 and normally these sections are held in alignment by a spring I01 bearing against the outer portion of section I05. The arm I00 is electrically insulated from the casing 90.

Such arm section I05 carries a pin I08 formed of high carbon steel or its equivalent, and normally extending across the coin slot or the upper portion of chute 92. A stop pin I09 normally extends slightly across the upper side of the arm I00 so as to maintain it in the full line position of Fig. 7 with the spring I02 tensioned. Rigid with the arm I00 is a relatively long pin IIO extending outwardly through an arcuate slot III in the housing 50 and projecting into a position at the underside of the hook I I2 for a telephone receiver.

In the use of this apparatus a person desiring to use the telephone, for example, removes the receiver from the hook H2 and the latter moves upwardly off the pin IIO. Next a nickel H3 is inserted through the slot 9| and engaging the dogs 95 rocks them downwardly to the dotted line positions against the action of the springs 91.

When the dogs are in the dotted line positions the nickel may pass between them and into engagement with the pin I08. It is noted that this pin is beveled on its upper side at IBM as shown in Fig. 8 and when the nickel engages the pin the nickel has moved downwardly to such an extent as to permit the dogs to be returned to I their normal positions by the springs 01: This places the dogs in positions preventing movement of the nickel upwardly out of the coin slot or preventing return movement of the nickel.

As downward movement of the nickef i continues I it causes the arm section I05 to swing rearwardly about the hinge I 00 as a pivot and sill-1st the action of the spring I01 thus also movingthe pin I00 outwardly.

As the arm section I05 is thus from beneath the stop pin I00 there is nothin'giiurther to hold the arm and the spring I02 swings the arm upwardly. As this occurs the I00 is wiped across the nickel being held against it by the spring I01 and an electrical current is generated. The dogs 05 prevent the coin being forced upwardly under this wiping action. Wires H4 and H5 corresponding with the wires 00 and 42 of Fig. 1 connect the casing 00 and the arm I00, respectively, with the meter so that my current generated as described is impressed on the meter and the same actuated to release the bar 45 as previously set forth. After pin I00 is wiped across the coin this coin drops in chute 92 onto pin 50, and if it was a nickel so as to generate current to operate the meter the lever arm 45 will be released as above described, permitting the coin to go down branch chute 00 to complete the telephone connection to the central oihce. When the user has finished with the telephone he returns the receiver to the hook H2 and this draws the hook downwardly, and the latter engaging pin IIO moves it downwardly carrying the arm I00 back to normal position in which position it is again held by the pin I00 until the insertion of another coin shifts the arm section I05 from beneath such pin. In this position the end of pin I00 engages the casing 00 at the side of the coin chute and thus automatically short circuits the meter coil to prevent this coil and its needle swinging by Jars, etc.

If in this case the coin is not a nickel coin the meter will not be operated and the lever will not be released the same as described in connection with the other forms.

It will now be understood that with each oi the several devices shown, on the insertion or feeding of a nickel to the apparatus a current will be generated and impressed on a meter and the nickel permitted to pass through the proper path so as to release a coin controlled mechanism as a telephone, dispenser, etc. If any coin or slug other than a nickel is fed to the machine then an electrical current is not generated and the meter is not actuated and such other coin or slug is directed along a different path and prevented from releasing the coin controlled mechanism which is being guarded. In each case the coil of the meter is short circuited so as to prevent anyone causing movement of the needle or arm 44 of the meter by thumping or otherwise jarring the mechanism.

It will be clear that the relative wiping action between the coin and the member of a different metal, such as-the member 26, 66 and 01, or I00. is secured whether the member is shifted or wiped across the coin or the coin is shifted or wiped across the member, and therefore when the statement of the member being relatively wiped across a coin or similar statement is made, it is used in a generic sense to mean either operation.

Having thus set forth the nature of my invention, what I claim is:

1. In a device of the character described for separating nickel coins from the usual slugs of materially dilierent metal, a. coin clot including a pair oi paths leading therefrom, an electric meter, means controlled by the meter to determine. the path a coin in the slot will take, said means being arranged to normally cause the coin to take one path and when the meter is energized to cause it to take the other path, a member composed 01 high carbon steel, means arranged for causing a relative wiping action between the member and a coin in the slot, and means for electrically connecting said member and the coin with the meter during the wiping operation.

2. In a device 0! the character described, a coin slot including a pair of paths leading therefrom,-

an electric meter including a coil and an arm operated by the coil on energizing of the latter, means associated with the slot normally shorting the circuit 0! the coil, means controlled by saidarm to determine the path a coin in the slot will take, said means being normally in a position to cause the coin to take one path and held in that position by the arm, a member composed of a different metal from that of the alloy of a nickel coin and having the characteristic of when relatively wiped across a nickel coin of generating sufllcient electromotive force to energize the meter to shift said arm to release said path determining means and when wiped across the usual slug ofv a materially different metal of not generating suflicient electromotive force to operate the meter, means arranged for causing wiping action between the member and a coin in the slot, and means electrically connecting said member and the coin in circuit with the coil during the wiping operation.

3. In a device of the character described for separating nickel coins from the usual slugs of materially different metal, a coin slot including a pair of paths meter, means controlled by the meter to determine the path a coin in the slot will take, said means being arranged to normally cause the coin to take one path and when the meter is energized to cause it to take the other path, a member composed of means including a steel contact, means arranged for causing a relative wiping aca relative leading therefrom, an electric carrying the coin across tion between the contact and a coin in the slot with a rapid snap movement, and means electrically connecting the contact and the contact in circuit with the meter during the wiping op ation.

4. In a device of the character described tor separating nickel coins mm the usual slugs of materially diirerent metal. a coin slot including a pair of slots leading thereirom, an electric meter, means controlled by the meter to determine the path a coin in the slot will takersaid means being'arranged to normally cause the coin to take one path and when the meter is energized to cause it to take the other path, a steel pin projecting into the path of a coin ted to said slot. a spring to shift one of the elements consisting of the coin and the pin across the other. said pin being yieldingly mounted to hold against the coin until the spring is compressed so that the spring snaps the one element across the other with the pin wiping against the side of the coin, and means electrically connecting the pin and coin in circuit with the meter during the wiping operation.

5. In a device of the v separating nickel coins from the usual slugs of materially different'metal, a'coin slot including a pair of slots leading therefrom, an electricfmeter, means controlled by the meter to determine the path a coin in the slot will take, said means being arranged to normally cause the coin to take one path and when the meter is energized to cause it to take the other path, a steel pin projecting into the path of a coin fed to said slot,,a member shiitable to carry a coin past said pin, a spring for shifting said member, hand operated means to compress the spring to have it shift the memher from one position to the other, said pin being yieldingly mounted to hold the coin and member until the spring is compressed so-that the spring shifts the member and coin with a snap action wiping against the side of the coin, and means electrically connecting the coin and pin in circuit with the meter during the wiping operation.

WILLIAM C. MITCHELL.

character described for 40 the pin with the latter 

